Obesity paradox extends to PE patients

SAN ANTONIO – Patients with pulmonary embolism who were obese paradoxically had a lower mortality risk, compared with those who are not obese, according to results of a retrospective analysis covering 13 years and nearly 2 million PE discharges.

Andrew D. Bowser/MDedge News

Dr. Zubair Khan

The obese patients in the analysis had a lower mortality risk, despite receiving more thrombolytics and mechanical intubation, said investigator Zubair Khan, MD, an internal medicine resident at the University of Toledo (Ohio) Medical Center.

“Surprisingly, the mortality of PE was significantly less in obese patients,” Dr. Khan said in a podium presentation at the annual meeting of the American College of Chest Physicians. “When we initiated the study, we did not expect this result.”

The association between obesity and lower mortality, sometimes called the “obesity paradox,” has been observed in studies of other chronic health conditions including stable heart failure, coronary artery disease, unstable angina, MI, and also in some PE studies, Dr. Khan said.

The study by Dr. Khan and his colleagues, based on the National Inpatient Sample (NIS) database, included adults with a primary discharge diagnosis of PE between 2002 and 2014. They included 1,959,018 PE discharges, of which 312,770 (16%) had an underlying obesity diagnosis.

Obese PE patients had more risk factors and more severe disease but had an overall mortality of 2.2%, compared with 3.7% in PE patients without obesity (P less than .001), Dr. Khan reported.

Hypertension was significantly more prevalent in the obese PE patients (65% vs. 50.5%; P less than .001), as was chronic lung disease and chronic liver disease, he noted in his presentation.

Obese patients more often received thrombolytics (3.6% vs. 1.9%; P less than .001) and mechanical ventilation (5.8% vs. 4%; P less than .001), and more frequently had cardiogenic shock (0.65% vs. 0.45%; P less than .001), he said.

The obese PE patients were more often female, black, and younger than 65 years of age, it was reported.

Notably, the prevalence of obesity in PE patients more than doubled over the course of the study period, from 10.2% in 2002 to 22.6% in 2014, Dr. Khan added.

The paradoxically lower mortality in obese patients might be explained by increased levels of endocannabinoids, which have shown protective effects in rat and mouse studies, Dr. Khan told attendees at the meeting.

“I think it’s a rich area for more and further research, especially in basic science,” Dr. Khan said.

Dr. Khan and his coauthors disclosed that they had no relationships relevant to the study.